U.S. patent application number 12/594718 was filed with the patent office on 2010-05-13 for backplane to mate boards with different widths.
Invention is credited to Mats Rimborg.
Application Number | 20100120266 12/594718 |
Document ID | / |
Family ID | 38859022 |
Filed Date | 2010-05-13 |
United States Patent
Application |
20100120266 |
Kind Code |
A1 |
Rimborg; Mats |
May 13, 2010 |
Backplane To Mate Boards With Different Widths
Abstract
The invention provides a backplane (406, 601) for a magazine
(401) equipped with sockets (407, 504, 603) having a number of
contact points (604, 703) arranged to receive a mating plug (409,
501) mounted at a rear edge of a circuit board assembly (408) with
a certain width. In this way an electrical contact is established
between the circuit board assembly and the backplane wherein the
sockets are arranged such as to accomplish rows (602) of the
contact points in a direction perpendicular to the first circuit
board surface (411) and the second circuit board surface (412). The
invention allows a magazine to be equipped with circuit board
assemblies of different widths. The invention further provides a
magazine equipped with the backplane and a method on how to arrange
the sockets.
Inventors: |
Rimborg; Mats; (Goteborg,
SE) |
Correspondence
Address: |
ERICSSON INC.
6300 LEGACY DRIVE, M/S EVR 1-C-11
PLANO
TX
75024
US
|
Family ID: |
38859022 |
Appl. No.: |
12/594718 |
Filed: |
April 3, 2007 |
PCT Filed: |
April 3, 2007 |
PCT NO: |
PCT/EP07/53261 |
371 Date: |
October 5, 2009 |
Current U.S.
Class: |
439/65 ;
29/842 |
Current CPC
Class: |
Y10T 29/49147 20150115;
H05K 7/1454 20130101 |
Class at
Publication: |
439/65 ;
29/842 |
International
Class: |
H01R 12/00 20060101
H01R012/00; H05K 3/30 20060101 H05K003/30 |
Claims
1. A backplane for a magazine, the backplane comprising a first
backplane surface and an opposite second backplane surface, the
backplane being equipped with sockets on the first backplane
surface, the sockets having a number of contact points and are
arranged to receive a mating plug mounted at a rear edge of a
circuit board assembly for establishing an electrical contact
between the circuit board assembly and the backplane, the circuit
board assembly having a certain width and having a first circuit
board surface and an opposite second circuit board surface, both
circuit board surfaces being perpendicular to the backplane, and
further that the sockets are arranged such as to accomplish rows of
the contact points being perpendicular to the first circuit board
surface and the second circuit board surface wherein the sockets
have open short ends and two side walls along each longitudinal
side of the socket and at least one row of connector pins between
the side walls, the sockets being mounted short end to short end
with the side walls aligned perpendicular to the first circuit
board surface and the second circuit board surface thus creating at
least one stripe of sockets in a direction perpendicular to the
first circuit board surface and the second circuit board
surface.
2. The backplane according to claim 1, wherein the at least one
stripe of sockets extend along part of a width of the backplane or
along the full width of the backplane.
3. The backplane according to claim 1, wherein there is an equal
distance between the contact points in a direction perpendicular to
the first circuit board surface and the second circuit board
surface.
4. The backplane according to claim 1, wherein the contact points
in the sockets are realized as male contacts or contact pins.
5. The backplane according to claim 1, wherein the contact points
in the sockets are realized as female contacts.
6. The backplane according to claim 1, wherein the width of the
circuit board assemblies within a magazine can vary within the
limitation of being a multiple of a selected pitch, being a basic
width of the circuit board assembly.
7. The backplane according to claim 1, wherein board positions for
two communication switch boards are allocated in the middle of the
magazine, one of which is redundant.
8. The backplane according to claim 7, wherein the communication
boards are made according to the Ethernet standard.
9. The backplane according to claim 1, wherein the plugs have ribs
on each side, perpendicular to the first circuit board surface and
the second circuit board surface, which are adapted to mate with
corresponding slots at inner sides of the side walls to the
socket.
10. The backplane according to claim 1, wherein power supply to the
circuit board assemblies is arranged by connecting two rows and of
the connector pins with broad strips of a conductive material, each
strip connecting one row of connector pins.
11. The backplane according to claim 10, wherein the conductive
material is copper.
12. The backplane according to claim 1, wherein IPMI connection to
the circuit board assemblies is arranged by connecting two rows of
the connector pins with strips of a conductive material, each strip
connecting one row of connector pins.
13. A magazine equipped with a backplane, the backplane comprising
a first backplane surface and an opposite second backplane surface,
the backplane being equipped with sockets on the first backplane
surface, the sockets having a number of contact points and are
arranged to receive a mating plug, mounted at a rear edge of a
circuit board assembly for establishing an electrical contact
between the circuit board assembly and the backplane, the circuit
board assembly having a certain width and having a first circuit
board surface and an opposite second circuit board surface, both
circuit board surfaces being perpendicular to the backplane, and
further that the sockets are arranged such as to accomplish rows of
the contact points being perpendicular to the first circuit board
surface and the second circuit board surface wherein the sockets
have open short ends and two side walls along each longitudinal
side of the socket and at least one row of connector pins between
the side walls, the sockets being mounted short end to short end
with the side walls aligned perpendicular to the first circuit
board surface and the second circuit board surface thus creating at
least one stripe of sockets in a direction perpendicular to the
first circuit board surface and the second circuit board
surface.
14. The magazine according to claim 13, wherein the at least one
stripe of sockets extend along part of a width of the backplane or
along the full width of the backplane.
15. The magazine according to claim 13, wherein there is an equal
distance between the contact points in a direction perpendicular to
the first circuit board surface and the second circuit board
surface.
16. The magazine according to claim 13, wherein the contact points
in the sockets are realized as male contacts or contact pins.
17. The magazine according to claim 13, wherein the contact points
in the sockets are realized as female contacts.
18. The magazine according to claim 13, wherein the width of the
circuit board assemblies within a magazine can vary within the
limitation of being a multiple of a selected pitch, being a basic
width of the circuit board assembly.
19. The magazine according to claim 13, wherein board positions for
two communication switch boards are allocated in the middle of the
magazine, one of which is redundant.
20. The magazine according to claim 19, wherein the communication
boards are made according to the Ethernet standard.
21. The magazine according to claim 13, wherein the plugs have ribs
on each side, perpendicular to the first circuit board surface and
the second circuit board surface, which are adapted to mate with
corresponding slots at inner sides of the side walls to the
socket.
22. The magazine according to claim 13, wherein power supply to the
circuit board assemblies is arranged by connecting two rows and of
the connector pins with broad strips of a conductive material, each
strip connecting one row of connector pins.
23. The magazine according to claim 22, wherein the conductive
material is copper.
24. The magazine according to claim 13, wherein IPMI connection to
the circuit board assemblies is arranged by connecting two rows of
the connector pins with strips of a conductive material, each strip
connecting one row of connector pins.
25. A method for arranging sockets on a backplane, wherein the
sockets are mounted short end to short end with side walls aligned
perpendicular to the first circuit board surface and the second
circuit board surface thus creating at least one stripe of sockets,
extending along part of the width of the backplane or along the
full width of the backplane, in a direction perpendicular to the
first circuit board surface and the second circuit board surface.
Description
TECHNICAL FIELD
[0001] The invention relates to the technical field of backplanes
for electronic assembly magazines.
BACKGROUND
[0002] The hardware of electronic systems such as e.g.
telecommunications systems comprises a number of circuit board
assemblies. Based on the technology of today these boards are
typically mounted in magazines having horizontal shelves. FIG. 1
shows a magazine 101 with a top shelf 102, a bottom shelf 103, top
rails 104 and bottom rails 105 and a backplane 106 with sockets
107. When the circuit board assembly 108 is inserted in the
magazine it is guided through the top and bottom rails towards a
socket 107 mounted to the backplane. The circuit board assembly has
a plug 109 at an edge portion of the circuit board assembly. The
plug and socket are shown more in detail in the enlarged section C
in FIG. 1. The rails are located in relation to the socket or
sockets at the back plane such that the plug is guided to mate with
the socket or sockets and thus establishing an electrical contact
between the circuit board assembly and the backplane. The backplane
includes electrical connections to allow for communications between
the circuit board assemblies in the magazine and communications
with other parts of the telecommunications system.
[0003] FIG. 2 shows how to arrange for further guidance of the
circuit board assembly 108 towards the socket. The plug 201 is
supplied with ribs 202 at each side which are adapted to mate with
corresponding slots 203 at the inner side walls of the socket
204.
[0004] FIG. 3 shows the backplane 301 with vertical stripes of
sockets 302. The enlarged section A shows the sockets 303 and
connector pins 304.
[0005] Backplane designs following different standards such as VME
(Versa Module Eurocard), cPCI (Compact Peripheral Component
Interconnect) and ATCA (Advanced Telecom Computing Architecture)
have traditionally been designed with a fixed distance between the
boards, e.g. 0.8 inch for VME and cPCI and 1.2 inch for ATCA.
[0006] The optimal board width varies depending on what's mounted
on the board and the amount of power and cooling required. A simple
interface board may only need a 10 mm slot, a CPU (Central
Processing Unit) board can be fitted in a 15 mm slot, if PMC
(Peripheral component interconnect Mezzanine Card) adapters are
used 20 mm is more suitable, and for boards with AMC (Advanced
Mezzanine Card) adapters 25 mm is needed. A slot is defined as the
width required for a certain circuit board assembly.
[0007] When the backplane basic board width has been decided all
board widths must be adapted to a multiple of this value, and
regardless of what is chosen it will never be optimal for all
designs. Different boards will not be able to coexist in the same
magazine unless they are designed for the same basic board width.
This basic board width is henceforth called the pitch for the
backplane. If a pitch of 15 mm is chosen for a backplane this means
that all boards belonging to the magazine with this backplane have
to have a width being a multiple of 15 i.e. 15, 30, 45 . . .
millimetres.
[0008] A sufficiently small pitch, such as 5 mm, may in theory be
used to overcome this problem, but in practice the sockets needed
to implement this design will be very narrow, and the number of
connections to each possible board position, whether they are used
or not, will be unnecessarily large. For practical reasons this
solution is not useful.
[0009] Hence there is a need to accommodate circuit board
assemblies with a greater flexibility in using different widths
within the same magazine in order to accomplish efficient use of
the magazine space available.
SUMMARY
[0010] It is therefore the objective of the invention to provide a
backplane for a magazine, as well as a magazine and a method for
arranging sockets, the backplane comprising a first backplane
surface and an opposite second backplane surface, the backplane
being equipped with sockets on the first backplane surface, the
sockets having a number of contact points and are arranged to
receive a mating plug, mounted at a rear edge of a circuit board
assembly for establishing an electrical contact between the circuit
board assembly and the backplane, the circuit board assembly having
a certain width and having a first circuit board surface and an
opposite second circuit board surface, both circuit board surfaces
being perpendicular to the backplane, which can solve the problem
to conveniently accommodate circuit board assemblies with different
widths within the same magazine.
[0011] This object is achieved by a backplane where the sockets are
arranged such as to accomplish rows of the contact points being
perpendicular to the first circuit board surface and the second
circuit board surface.
[0012] Instead of placing the backplane sockets in stripes parallel
to the circuit board surfaces, mating one board per stripe, the
idea is to position the stripes of sockets perpendicular to the
circuit board surfaces and be able to mate boards with different
widths to a wider or narrower part of one or several stripes in a
flexible manner. Each circuit board assembly can have several plugs
along a rear edge of the board, each plug mating with a stripe of
sockets being perpendicular to the circuit board surfaces.
[0013] For telecommunications equipment the backplane may provide
connections to for example: [0014] Redundant 48 V power supply
[0015] Redundant 10/100/1000 Mbps Ethernet for control and/or
payload [0016] One ore several redundant 10 Gbps Ethernet for
payload [0017] IPMI (Intelligent Platform Management Interface)
[0018] The list is not exhaustive.
[0019] Connections to different resources may be repeated with
different intervals. Power needs to be available within every basic
circuit board assembly width i.e. within the selected pitch, but 10
Gbps Ethernet can for most cases be limited to every second or
every third pitch. This is an implementation decision within the
scope of the invention.
[0020] A certain pitch has to be decided for each backplane and is
fixed for each backplane. However the pitch defines the basic
circuit board assembly width and hence the smallest width possible
for the circuit board assembly. If a pitch of 5 mm is selected then
the circuit board assemblies can have widths or slot sizes which
are multiples of 5 mm, i.e. 5, 10, 15, 20 . . . and they can be
mixed arbitrarily within the same magazine.
[0021] All available space within a magazine with a backplane with
flexible slot size may be used efficiently regardless of how
different board types are combined. This makes it possible to
create compact solutions with a minimal infrastructure overhead
such as power supplies, chassis and interconnections.
[0022] Further advantages are achieved if the invention also is
given one or several of the characteristics of the dependent claims
such as e.g. [0023] equal distance between contact points in a
direction perpendicular to the circuit board surfaces [0024] the
contact points in the sockets are realized as male or female
contacts [0025] creating one or several stripes of sockets in a
direction perpendicular to the circuit board surfaces and extending
over part of the width of the backplane or along the full width of
the backplane. [0026] board positions for communication switch
boards are allocated in the middle of the magazine [0027]
communication boards are according to Ethernet standard [0028] the
plugs have ribs, on each side perpendicular to the circuit board
surfaces, which are adapted to mate with corresponding slots at
inner sides of side walls of the sockets [0029] power supply to the
circuit board assembly is arranged by connecting two rows of
connector pins with strips of a conductive material such as copper
[0030] IPMI (Intelligent Platform Management Interface) connection
is arranged in a similar way as the power supply.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 schematically shows a perspective view of a prior art
magazine
[0032] FIG. 2 schematically shows a plug and socket with guiding
means according to prior art.
[0033] FIG. 3 schematically shows a perspective view of a backplane
according to prior art.
[0034] FIG. 4 schematically shows a magazine with a backplane
according to the invention.
[0035] FIG. 5 schematically shows a plug and socket with guiding
means according to the invention.
[0036] FIG. 6 schematically shows a perspective view of a backplane
according to the invention.
[0037] FIG. 7 schematically shows an arrangement for power supply
distribution to the circuit board assemblies.
[0038] FIG. 8 schematically shows an example of how to allocate
10/100/1000 Mbps Ethernet connections.
[0039] FIG. 9 schematically shows an example of how to implement 10
Gbps Ethernet connections.
[0040] FIG. 10 schematically shows a method how to arrange sockets
on a backplane.
DETAILED DESCRIPTION
[0041] The invention will in the following be described in detail
with reference to the drawings.
[0042] A backplane according to the invention is described in FIG.
4 which shows a magazine 401 with a top shelf 402, a bottom shelf
403, top rails 404 and bottom rails 405 and a backplane 406 with
sockets 407. When a circuit board assembly 408 is inserted in the
magazine it is guided through the top and bottom rails towards the
socket 407 mounted to the backplane. The circuit board assembly has
a plug 409 at an edge portion of the circuit board assembly. The
plug and the socket are shown more in detail in enlarged section D
in FIG. 4. The rails are located in relation to the socket or
sockets at the back plane such that the plug is guided to mate with
the socket or sockets and thus establishing an electrical contact
between the circuit board assembly and the backplane. The circuit
board assembly has a first circuit board surface 411 and an
opposite second circuit board surface 412. The backplane, which
e.g. can be manufactured as a conventional Printed Circuit Board
(PCB), includes electrical connections, in one or several layers,
to allow for communications between the circuit board assemblies in
the magazine and communications with other parts of the
telecommunications system. The backplane can e.g. be manufactured
by glass fibre reinforced epoxy, such as FR-4.
[0043] FIG. 5 shows how to arrange for further guidance of the
circuit board assembly 408 towards the socket 504. The plug 501 is
supplied with ribs 502 at each side which are adapted to mate with
corresponding slots 503 at inner side walls of the socket 504.
[0044] The backplane 406 can have one or several stripes 410 of
sockets 407 in a direction perpendicular to the first circuit board
surface 411 and the second circuit board surface 412. The distance
between the stripes is adapted to the needs for the intended
application. The stripes can be located as close to each other as
allowed by the physical design of the sockets. The distance between
the plugs on the rear edge of the circuit board assembly has to be
designed so as to fit into the socket locations on the
backplane.
[0045] FIG. 6 shows the backplane 601 with stripes 602 of sockets
603 in a direction perpendicular to the first circuit board surface
411 and the second circuit board surface 412. The enlarged section
B shows rows 605 of contact points 604, in the direction
perpendicular to the first circuit board surface 411 and the second
circuit board surface 412. In this example the contact points are
realized as connector pins. The enlarged section B also shows the
sockets 603, short ends 606 and side walls 607 and 608 of the
socket 603. The backplane has a width 611, a first backplane
surface 609 and an opposite second backplane surface 610.
[0046] A practical basic circuit board assembly width or pitch, can
be 5 mm. In the description connector points in the socket are
henceforth exemplified with connector pins even if also female
contact points may be used. The spacing between the connector pins,
in a direction perpendicular to the first circuit board surface 411
and the second circuit board surface 412, must be adapted to the
pitch. If the pitch is 5 mm the connector pin spacing can be
5/1=5.0 mm, 5/2=2.5 mm, 5/3=1.67 mm, 5/4=1.25 mm or 5/5=1.0 mm.
Wider spacing may be desirable for power supply pins and closer
spacing for data signals. The spacing between the connector pins,
in the direction perpendicular to the first circuit board surface
411 and the second circuit board surface 412, within a socket/s or
a stripe/s on the backplane is normally the same, i.e. the
backplane has normally a fixed spacing between connector pins in
this direction. The spacing between connector pins, in a direction
parallel to the first circuit board surface 411 and the second
circuit board surface 412, within a socket is normally the same as
the spacing in the direction perpendicular to the first circuit
board surface 411 and the second circuit board surface 412 but may
also be different. Within a stripe of sockets the distance between
connector pins, in the direction parallel to the first circuit
board surface 411 and the second circuit board surface 412, is
usually constant but may also differ from socket to socket
depending on how the magazine is equipped with different types of
circuit board assemblies having different types of plugs. The
thickness of the connector pins are typically the same within a
stripe of sockets but may vary from row to row and socket to
socket.
[0047] The magazine has a number of possible board positions
depending on the selected pitch. If a magazine has an effective
width of 300 mm and a pitch of 5 mm, the magazine has 60 possible
board positions. If the magazine is equipped only with circuit
board assemblies with a width of 10 mm, the magazine can hold 30
boards, each board taking up two positions.
[0048] The backplane normally has two redundant predefined
locations reserved for communication switch boards, henceforth
exemplified with Ethernet, to provide connectivity within the
magazine, just like any other modern fixed slot size backplane.
Ethernet is a common communication protocol used in the ATCA
standard (Advanced Telecom Computing Architecture). However other
communication protocols as e.g. PCI Express (Peripheral Component
Interconnect) or RapidIO may be used. The predefined locations for
the Ethernet switch boards are in the middle of the magazine
according to the ATCA standard. Other standards can have other
predefined Ethernet switch board positions. If an Ethernet board
with a width of 15 mm is used and the backplane has a pitch of 5
mm, each Ethernet board will take up three board positions of the
magazine.
[0049] Each position is identifiable by means of a unique bit
pattern. This could be achieved by coding a binary, parity checked,
data word at each possible board position of the backplane by using
a combination of a number of grounded and ungrounded connector
pins, unique for each board position.
[0050] Each board within a magazine should receive an input with
information about the number of board positions, counted from one
side of the magazine, which have been used. Each board should also
forward information to the next one about which board positions it
has used itself, i.e. increment the received number by one, or
possibly more in case of a complex board which utilizes more than
one board position. If the backplane contains a control bus, such
as IPMI (Intelligent Platform Management Interface), it could be
used to transfer this information.
[0051] Unused board positions should need no external electrical
terminations, and the connection information should be passed
through such slots passively.
[0052] The mechanical guide rails for the circuit boards assemblies
must have the same spacing as the backplane pitch. Special
consideration should be taken when designing this to allow adequate
air flow for cooling to pass through them. The rails and the top
and bottom shelves can e.g. be perforated.
[0053] FIG. 7 shows how the power supply to the circuit board
assemblies in the magazine can conveniently be arranged by
connecting two rows 701 and 702 of connector pins 703 with broad
strips 704 and 705 of a conductive material as e.g. copper, each
strip connecting one row of connector pins.
[0054] The communication internally within the magazine and
externally can be arranged through e.g Ethernet, PCI Express
(Peripheral Component Interconnect) or RapidIO. Each circuit board
assembly 408 normally has a connection to a communication means
here exemplified by Ethernet. Some circuit boards might only pick
up power supply from the backplane and external communication is
arranged by means of connectors at the front panel of the circuit
board assembly. In order to save connector pins, various solutions
are possible. The solutions are based on that not all possible
board positions have available Ethernet connections. A standard
Ethernet connection for 10/100/1000 Mbps (Megabits per second)
requires 8 contact pins on the socket. A 300 mm magazine with 5 mm
pitch has 60 board positions. If an Ethernet connection should be
available at each position it would require 60.times.8=480
connector pins only for Ethernet connections.
[0055] Another way is to use the information about the number of
boards and the average widths of the boards together with the
physical position and use this to select one connection out of
several available at each position. In this case a selected number
of connections are available for the whole magazine, and as long as
not all narrow boards are placed to one side and all wide boards to
the other side it will be possible to select a separate connection
for each used board position. FIG. 8, which can be imagined to
extend further to the right, shows 13 board positions 801-813, each
board position has a width of 5 mm, i.e. the pitch is 5 mm. Each
square 814 at a board position has 8 connections. With a connector
pin distance of 5/4=1.25 mm, the pins can be arranged in two rows
with 4 pins/row. The squares are arranged in a matrix in an x/y
plane defined by coordinate symbol 815. Squares 1/3-4/3 has access
to an Ethernet 1 connection, 1/2-4/2 Ethernet 2, 1/1-4/1 to
Ethernet 3 and so on. If 10 mm boards are used they will require
two board positions each. Board nr 1 will require board position 1
and 2 and can use Ethernet 1, board nr 2 requires positions 3 and 4
and can use Ethernet connection nr 2 and so on. Board nr 5 will use
positions 9 and 10 and Ethernet 5. When it comes to board nr 6 it
will not find a free Ethernet connection as can be seen in FIG. 8.
Board nr 6 has to have a width of 15 mm to be able to pick up
Ethernet connection nr 6. This solution will limit the flexibility
for Ethernet connections but it will save connector pins needed and
it will have sufficient flexibility for most practical applications
when boards of different widths are mixed. This is just an
illustration of one possible solution. Many other solutions are of
course possible within the scope of the invention.
[0056] 10 Gbps (Gigabits per second) Ethernet could be implemented
similarly to 10/100/1000 Mbps Ethernet. FIG. 9 shows the same 10
Gbps Ethernet port connected to two adjacent positions, and three
boards of different widths use one Ethernet port each. FIG. 9 also
shows 7 board positions 901-907, each position of 5 mm width. Each
square 908 has 16 connector pins which is required for 10 Gbps when
10 Gbase CX-4 standard is used. Board no 1 has a width of 10 mm,
distance 909, and can use 10G no 1, board 2 has a width of 15 mm,
distance 910, and can use 10G no 2, board 3 has a width of 10 mm,
distance 911, and can use 10G no 3, and so on. (10 Gbase-T standard
only requires 8 connector pins but has other limitations)
[0057] The IPMI (Intelligent Platform Management Interface)
standard defines a set of common interfaces used to monitor system
status and to manage the system. IPMI is a multidrop I.sup.2 C
(Inter-integrated circuit) based architecture and could easily be
implemented in the same way as the power supply as described in
association with FIG. 7 above. In this case the conductive strips
can be made narrower as very low power is needed.
[0058] If circuit board assemblies, designed for use with a
backplane with stripes of sockets in the direction parallel to the
first circuit board surface 411 and the second circuit board
surface 412, is desired to be used together with the backplane
according to the invention this can be solved by increasing the
depth of the magazine and insert an adapter between the circuit
board assembly and the backplane. The adapter contains logics and
mechanical adjustments needed for the conversion.
[0059] FIG. 10 schematically illustrates a method of arranging 1001
sockets on a backplane. The sockets are mounted 1002 short end to
short end with side walls aligned 1003 in the direction
perpendicular to the first circuit board surface 411 and the second
circuit board surface 412 thus creating at least one stripe of
sockets in the direction perpendicular to the first circuit board
surface 411 and the second surface board surface 412. The stripe
can extend along the full width 611 of the backplane or part of the
width 611 of the backplane.
[0060] The invention has been described for applications within the
telecommunications field but can e.g. also be used within the field
of computers and any other field within electronics where there is
a need for a backplane to connect a number of circuit board
assemblies.
[0061] The invention is not limited to the embodiments above, but
may vary freely within the scope of the appended claims.
* * * * *